Traditionally food warming devices for banquet style serving fall into four basic categories: Chafing dishes, stainless steel drop-in food warmers utilizing coiled heating elements, steam tables using coiled heating elements for convective heat transfer through a liquid medium such as water jacket, and infrared heat lamps; all of which require much care in operation due to the magnitude of heat produced and which are cost prohibitive and bulky for home use. It is common knowledge that using such devices can be hazardous. Many fire authorities have banned the use of open flame chafing dishes in schools and nursing facilities, or have restricted their use in other settings. Plaintiffs incurring injuries from the use of chafing dishes and steam tables have been awarded damages.
More recently, so called flexible heaters have been utilized for keeping food warm in commercial establishments. To date, these custom manufactured flexible heaters have fallen into two basic categories: those designed to fit either into steam warming tables where the temperature transfer between the device and the food is mediated by a layer of water, or by direct contact with food as in a warming cabinet. Several aspects of the construction of these flexible heaters make them unsuitable for table-top banquet style serving: The power to these heaters is integrated into the temperature control circuitry of the food warming cabinet or steam table. As such, these cannot be directly connected to 120 VAC, or operate independent of their host container. In addition, because the heaters are constructed for application to a stainless steel surface, they lack measures to prevent overheating of the surface to which they are affixed. Manufacture of these heaters involves vulcanizing a wire wound heating element where the wire elements are sheathed in fiberglass wrap, between two sheets of an elastomeric polymer such as silicone, neoprene or Kapton®. The fiberglass wrap is required because it adheres to silicone and as an aid in maintaining the pattern of the wire element during the lamination process. Because they are commonly constructed of layered sheet silicone that is manufactured on rolls, the finished product tends to naturally curl. Additionally, the manufacturing process common to flexible heaters using wire wound resistive heating elements produces a heating apparatus where the outline of the heating elements protrudes above the otherwise planar surface of the top layer. This introduces friction points that will abrade quickly possibly exposing the heating element when objects are moved on and off the pad frequently.